Scroll compressor

ABSTRACT

A scroll compressor is disclosed. The scroll compressor includes a first scroll and a second scroll engaged with the first scroll and configured to perform an orbiting movement. The second scroll forms a compression chamber between the first scroll and the second scroll. The scroll compressor includes a frame positioned opposite the first scroll with the second scroll interposed therebetween. The scroll compressor also includes an oldham ring that has an annular ring portion and a key portion protruding from the ring portion. The key portion is slidably coupled to a key groove provided in the frame or in the second scroll to allow the second scroll to perform an orbiting movement with respect to the first scroll. The scroll compressor also include a reinforcing member coupled to the key portion. The reinforcing member is positioned between the key groove and the key portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims benefit of priority of KoreanApplication Nos. 10-2018-0028704 and 10-2018-0075994, filed on Mar. 12,2018 and Jun. 29, 2018, respectively, both of which are herein expresslyincorporated by reference in their entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure relates to a compressor, and more particularly,to a scroll compressor.

2. Description of the Conventional Art

A scroll type compressor is provided with an electric motor unit formedwith a rotary motor inside a closed casing, and provided with acompression unit composed of a fixed scroll and an orbiting scroll onone side of the electric motor unit, and the electric motor unit and thecompression unit are connected by a rotation shaft to transmit arotational force of the electric motor unit to the compression unit. Therotational force transmitted to the compression unit causes the orbitingscroll to perform an orbiting movement with respect to the fixed scrollto form a pair of two compression chambers composed of a suctionchamber, an intermediate pressure chamber, and a discharge chamber sothat refrigerant is sucked into both the compression chambers,respectively, and compressed and discharged simultaneously.

Such a scroll type compressor is provided with a rotation preventionmechanism for preventing a rotational movement of the orbiting scroll.The rotation prevention mechanism may be applied with an oldham ring ora pin-and-ring.

The pin-and-ring method is advantageous compared to the oldham ringmethod because of reliability improvement due to improvement of thedurability of the rotation prevention mechanism and suppression ofweight increase of the compressor due to the rotation preventionmechanism. On the contrary, the pin-and-ring method is relativelydisadvantageous in terms of assembly since a plurality of pins and ringsmust be respectively installed in the orbiting scroll and a member incontact therewith. Accordingly, research for improving the quality ofthe material of the oldham ring to replace the pin-and-ring method hasbeen continuously carried out.

In particular, when the scroll compressor is applied to an automotiveair conditioning system, the oldham ring may be formed of an aluminummaterial in consideration of the weight and machinability of thecompressor. When aluminum is applied to the oldham ring, it isadvantageous in reducing the weight of the oldham ring, and enhancingmachinability and productivity.

However, considering the weight of the compressor, it is advantageous tofabricate the oldham ring as well as the orbiting scroll, the main frameor the fixed scroll therearound with aluminum, and in this case, thefriction characteristics are significantly deteriorated since thematerials of an aluminum oldham ring and a counterpart friction surfaceare the same. Recently, technologies for improving the wear reliabilityof a key portion of the oldham ring have been introduced.

Prior Art 1 (US 2017-0234313 A) is a technology capable of enhancingwear resistance while reducing the weight of the oldham ring by forminga ring portion and a key portion of the oldham ring with differentmaterials. Prior Art 2 (KR 10-1997-0021751) is a technology of treatingthe surface of the oldham ring to suppress the oldham ring from beingdeposited to the orbiting scroll or the fixed scroll.

However, in the conventional scroll compressor as described above, whenthe ring portion and the key portion of the oldham ring are made ofdifferent materials, the ring portion and the key portion must berespectively fabricated and assembled, thereby complicating thefabrication process.

Furthermore, when the ring portion and the key portion of the oldhamring are formed of different materials and assembled, the key portionmay be inserted into the ring portion and assembled. However, in thiscase, a cross-sectional area in the region where the ring portion andthe key portion are assembled may be reduced, thereby weakening supportstrength with respect to the key portion. Due to this, the reliabilityof the oldham ring may be deteriorated. In addition, when assembling thering portion and the key portion, a gap may occur at a joint portionbetween the ring portion and the key portion due to a machining error oran assembly error, and as a result, when the compressor is driven, theorbiting scroll may be pushed out in a circumferential direction whilethe key portion is warped against the ring portion. Then, a gap betweenthe wraps may occur to decrease the compression efficiency whileincreasing the compression loss.

Furthermore, when the ring portion and the key portion are made ofdifferent materials, the coefficients of thermal expansion of the ringportion and the key portion are different from each other, andtherefore, the key portion may be detached from the ring portion or aphenomenon of idling may occur.

In addition, in the scroll compressor in the related art, a coatinglayer may be formed with lubricant on a surface of the oldham ring.However, it not only increases the fabrication cost due to the formationof an additional coating layer but also causes the coating layer to peeloff or wear during its prolonged use to damage the oldham ring orincrease the friction loss.

Besides, in the scroll compressor in the related art, in the case of atransverse type scroll compressor in which the axial direction of therotation shaft is horizontal or inclined at an angle of 45 degrees withrespect to the ground, most of oil between the frame and the orbitingscroll is discharged when the compressor stops because the frame and theorbiting scroll are arranged in parallel to the ground. Then oil may notremain around the oldham ring, and friction loss and abrasion may occurbetween the oldham ring and a portion coupled to the oldham ring due tooil shortage while restarting the compressor.

SUMMARY OF THE INVENTION

An object of the present disclosure is to provide a scroll compressorcapable of reducing a weight of an oldham ring to decrease an overallweight of the compressor when the oldham ring is applied thereto.

Moreover, an object of the present disclosure is to provide a scrollcompressor capable of forming an oldham ring with the same material asthat of a frame, an orbiting scroll, or a fixed scroll and the like, towhich the oldham ring is coupled.

Moreover, an object of the present disclosure is to provide a scrollcompressor capable of forming both members with the same material, andforming an oldham ring and the both members to which the oldham ring iscoupled with the same material.

Moreover, an object of the present disclosure is to provide a scrollcompressor capable of forming a ring portion and a key portionconstituting an oldham ring with the same material.

Furthermore, another object of the present disclosure is to provide ascroll compressor capable of enhancing machinability and productivityfor an oldham ring.

In addition, another object of the present disclosure is to provide ascroll compressor capable of preventing formation of a gap greater thanallowable value between a key portion of an oldham ring and a frame oran orbiting scroll or a key groove of a fixed scroll to which the keyportion is coupled to enhance efficiency.

Besides, another object of the present disclosure is to provide a scrollcompressor capable of securing the support strength of a key portionwith respect to a ring portion constituting the oldham ring to enhancereliability.

Moreover, another object of the present invention is to provide a scrollcompressor capable of suppressing a key portion from idling with respectto a ring portion constituting the oldham ring to enhance reliability.

Another object of the present disclosure is to provide a scrollcompressor capable of forming a ring portion and a key portionconstituting an oldham ring into a single body.

Another object of the present disclosure is to provide a scrollcompressor capable of preventing oil supply shortage between an oldhamring and a member in contact therewith in a transverse type motor-drivencompressor to which the oldham ring is applied.

Moreover, still another object of the present disclosure is to provide ascroll compressor capable of carrying a predetermined amount of oilbetween an oldham ring and a member in contact therewith.

Moreover, still another object of the present disclosure is to provide ascroll compressor capable of preventing the strength of an oldham ringfrom being deteriorated even when oil is carried.

In order to accomplish the objective of the present disclosure, theremay be provided a scroll compressor, including a first scroll; a secondscroll engaged with the first scroll to perform an orbiting movement;and an oldham ring provided with a ring portion formed in an annularshape, and a key portion protruded from the ring portion, the keyportion being slidably coupled to a key groove provided in the secondscroll to allow the second scroll to perform an orbiting movement withrespect to the first scroll, wherein the key portion of the oldham ringis formed of the same material as that of the second scroll.

Here, a reinforcing member made of a material different from that of thesecond scroll or the oldham ring may be provided between the key portionand the key groove.

Furthermore, the reinforcing member may be inserted into and coupled tothe key portion.

Furthermore, a release preventing portion for preventing the reinforcingmember from being released may be formed between the reinforcing memberand a member to which the reinforcing member is coupled.

In addition, in order to accomplish the objective of the presentdisclosure, there may be provided a scroll compressor, including a firstscroll; a second scroll that forms a compression chamber between thefirst scroll and the second scroll while being engaged with the firstscroll to perform an orbiting movement; an oldham ring provided with aring portion formed in an annular shape and a key portion protruded fromthe ring portion, the key portion being slidably coupled to a key grooveprovided in the second scroll to allow the second scroll to perform anorbiting movement with respect to the first scroll; and a reinforcingmember coupled to the key portion of the oldham ring, and providedbetween the key groove of the second scroll and the key portion of theoldham ring.

Here, a release preventing portion may be provided in the reinforcingmember to be inserted into and fixed to the key portion.

Furthermore, the release preventing portion may be formed to be bent orprotruded in a direction toward the key portion, and a releasepreventing groove is formed in the key portion to insert and fix therelease preventing portion.

Here, the reinforcing member may include a plurality of reinforcingsurfaces facing both circumference side surfaces of the key portion; aconnecting surface connecting respective one ends of the plurality ofreinforcing surfaces to each other to face an outer circumferential sidesurface of the key portion; and a plurality of fixing surfaces benttoward the reinforcing surfaces facing each other at respective theother ends of the plurality of reinforcing surfaces to face an innercircumferential side surface of the key portion.

Furthermore, a release preventing groove having a predetermined depth ina radial direction may be formed on an inner circumferential sidesurface of the key portion, and release preventing portions bent towardthe release preventing groove may be formed on both fixing surfaces ofthe reinforcing member.

Furthermore, a release preventing groove having a predetermined depth ina radial direction may be formed on an inner circumferential sidesurface of the key portion, and the release preventing groove may beformed to have one end open in an axial direction, and releasepreventing portions bent toward the release preventing groove may beformed on both fixing surfaces of the reinforcing member.

Furthermore, a release preventing groove having a predetermined depth ina radial direction may be formed on an inner circumferential sidesurface of the key portion, and the release preventing groove may beformed to have an engaging surface in a shape closed in an axialdirection, and both the fixing surfaces of the reinforcing member may beinserted into the release preventing groove and supported in an axialdirection by the engaging surface.

Furthermore, release preventing grooves having a predetermined depth maybe formed on both circumferential side surfaces of the key portion, andrelease preventing portions may be formed in a protrusion shape on bothreinforcing surfaces of the reinforcing member to be inserted into therelease preventing grooves.

Here, the reinforcing member may include a first reinforcing memberprovided to face one circumferential side surface of the key portion anda second reinforcing member provided to face the other circumferentialside surface of the key portion.

Furthermore, release preventing grooves having a predetermined depth inradial directions opposite to each other may be respectively formed onan outer circumference side surface and an inner circumferential sidesurface of the key portion, and the first reinforcing member and thesecond reinforcing member may respectively include reinforcing surfacesfacing both circumferential side surfaces of the key portion, aplurality of fixing surfaces respectively bent at both ends of thereinforcing surface, and a plurality of release preventing portionsrespectively bent toward the both release preventing grooves on theplurality of fixing surfaces.

Here, the reinforcing member may include a connecting surface facing oneaxial side surface of the key portion; and a plurality of fixingsurfaces respectively bent at both ends of the connecting surface toface both circumferential side surfaces of the key portion.

Here, the reinforcing member may be formed by bending a plate materialhaving rigidity so as to be brought into contact with at least threesides of the side faces of the key portion.

Furthermore, the key portion of the oldham ring may be formed of thesame material as that of the second scroll, and the reinforcing membermay be formed of a material different from that of the key groove of thesecond scroll or the key portion of the oldham ring.

Furthermore, for the oldham ring, the key portion and the ring portionmay be formed of the same material.

Furthermore, for the oldham ring, the key portion and the ring portionmay be formed as a single body.

Here, an oil storage unit may be provided at the oldham ring or a memberto which the oldham ring is coupled to store oil.

Furthermore, the oldham ring may include a ring portion formed in anannular shape; and key portions formed at intervals along acircumferential direction on the ring portion to be slidably insertedinto key grooves provided in the frame or the second scroll, wherein theoil storage unit is formed to be recessed by a predetermined depth inthe key portion toward the ground.

Furthermore, the oil storage unit may be formed on an outer side from akey root portion where the key portion starts to protrude from the ringportion.

Furthermore, the oil storage unit may include an oil storage membercapable of containing oil.

Furthermore, a communication hole being open toward the oil storage unitmay be formed on a surface of the reinforcing member facing the oilstorage unit.

In addition, in order to accomplish the objective of the presentdisclosure, there may be provided a scroll compressor, including a firstscroll; a second scroll that forms a compression chamber between thefirst scroll and the second scroll while being engaged with the firstscroll to perform an orbiting movement; a frame fixed in a radialdirection on an opposite side of the first scroll with the second scrollinterposed therebetween to support the second scroll in an axialdirection; and an oldham ring coupled between the second scroll and theframe or between the second scroll and the first scroll to suppress therotation of the second scroll, wherein an oil storage unit is providedat the oldham ring or a member to which the oldham ring is coupled tostore oil.

Here, the oldham ring may include a ring portion formed in an annularshape; and key portions formed at intervals along a circumferentialdirection on the ring portion to be slidably inserted into key groovesprovided in the frame or the second scroll, and formed with the oilstorage unit, wherein the oil storage unit is formed to be recessed by apredetermined depth on an outer side from a key root portion where thekey portion starts to protrude toward the ground surface of the keyportion.

In the scroll compressor according to the present disclosure, thereinforcing member may be provided between the key portion of the oldhamring and the key groove of the frame, the orbiting scroll or the fixedscroll to which the key portion is inserted, thereby preventing theoldham ring from being directly brought into contact with the frame, theorbiting scroll or the fixed scroll. Accordingly, the ring portion andthe key portion forming the oldham ring may be made of lightweightaluminum, thereby reducing the weight of the oldham ring and thecompressor to which the oldham ring is applied.

Moreover, in the oldham ring of the scroll compressor according to thepresent disclosure, the key portion of the oldham ring may be formed ofthe same material as that of the frame, the orbiting scroll or the fixedscroll coupled thereto while preventing frictional characteristics dueto a friction between homogeneous materials from be deteriorated.Accordingly, a friction between the oldham ring and a member to whichthe oldham ring is coupled may be reduced to suppress the damage of theoldham ring or the counterpart as well as to reduce a friction loss,thereby improving compressor efficiency.

Moreover, in the oldham ring of the scroll compressor according to thepresent disclosure, the ring portion and the key portion constitutingthe oldham ring may be formed as a single body, thereby facilitating thefabrication of the oldham ring. Furthermore, when the compressor isdriven, it may be possible to suppress a phenomenon in which the keyportion of the oldham ring is twisted in the key groove of thecounterpart so as to suppress the orbiting scroll from being pushed in acircumferential direction, thereby reducing a compression loss caused bya gap between the wraps. Furthermore, it may be possible to secure astrength against the root portion of the key portion protruded from thering portion so as to suppress the key portion from being damaged,thereby enhancing the reliability.

Moreover, in the oldham ring of the scroll compressor according to thepresent disclosure, the ring portion and the key portion constitutingthe oldham ring may be formed of a single body and the same material,thereby preventing the key portion from being excessively deformed oridling when the compressor is driven. Accordingly, it may be possible toprevent the behavior of the orbiting scroll from becoming unstable dueto the oldham ring.

Furthermore, in the scroll compressor according to the presentdisclosure, the reinforcing member may be provided between the keyportion of the oldham ring and the key groove of the frame, the orbitingscroll or the fixed scroll to which the key portion is inserted, and therelease preventing portion may be formed between an end of thereinforcing member and the corresponding key portion, thereby fixing thereinforcing member. Accordingly, it may be possible to effectivelysuppress the reinforcing member from being released from the keyportion, thereby increasing reliability.

Moreover, it may also be possible to form a protrusion in thereinforcing member and a groove in the corresponding key portion,respectively, thereby suppressing the reinforcing member from beingreleased. Through this, the shape of the reinforcing member and the keyportion to which the reinforcing member is coupled may be simplified,thereby reducing fabrication cost.

Moreover, the release preventing groove may be formed in the keyportion, but the axial direction of the release preventing groove may beformed in an open shape. Through this, the reinforcing member may bepushed and inserted in an axial direction to facilitate the assembly ofthe reinforcing member in the axial direction.

Moreover, the release preventing groove may be formed in the keyportion, but may also be formed in a shape in which the axial directionof the release preventing portion is closed and both the circumferentialdirections are open. Through this, it may not be required to bendadditional release preventing portions at both ends of the reinforcingmember, thereby facilitating the fabrication and assembly of thereinforcing member.

Moreover, the reinforcing member may also be formed to be inserted in anaxial direction. Through this, it may be possible to further facilitatethe assembly of the reinforcing member.

Moreover, a plurality of reinforcing members may be formed and assembledin both circumferential directions of the key portion. Through this, thereinforcing member may be formed to be small, thereby facilitatingassembly.

Moreover, the reinforcement member may be fixed by an elastic force.Through this, it may be possible to facilitate the assembly of thereinforcing member.

Furthermore, in the scroll compressor according to the presentdisclosure, the oil storage unit may be formed in the key portion of theoldham ring in a transverse motor-driven compressor to which the oldhamring is applied, thereby allowing a predetermined amount of oil toremain in the oil storage unit of the key portion even when thecompressor is stopped. Through this, it may be possible to suppress theshortage of oil feeding between the oldham ring and the frame or theorbiting scroll in contact therewith, thereby reducing friction loss andreducing the wear-out of the key portion or the key groove.

Moreover, by forming the oil storage unit in the key portion of theoldham ring and inserting an oil storage member into the oil storageunit, oil may be effectively stored between the oldham ring and theframe or the orbiting scroll in contact therewith, thereby furtherenhancing the foregoing friction loss reduction and wear-out preventioneffect.

Moreover, the oil storage unit provided in the key portion of the oldhamring may be formed out of the key root portion to suppress the strengthof the oldham ring from being deteriorated due to the oil storage unit,thereby preventing the life of the oldham ring from being shortened.

Moreover, by forming the ring portion and the key portion of the oldhamring with different materials and forming the oil storage unit prior tothe key portion, thereby enhancing the friction loss reduction andwear-out prevention effect while reducing the weight of the oldham ring.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 is a cross-sectional view showing an inside of a motor-drivencompressor as an example of a scroll compressor according to the presentdisclosure;

FIG. 2 is a cross-sectional view showing a state in which an oldham ringis coupled between a frame and an orbiting scroll in a compression unitaccording to FIG. 1;

FIG. 3 is an exploded perspective view showing the compression unitaccording to FIG. 2;

FIG. 4 is an exploded perspective view showing a state in which areinforcing member is separated from an oldham ring in the compressionunit according to FIG. 3;

FIG. 5 is a perspective view showing a state in which the reinforcingmember is coupled to the oldham ring in FIG. 4;

FIG. 6 is a cross-sectional view showing a state in which thereinforcing member is coupled to the oldham ring and inserted into a keygroove of an orbiting scroll in a radial direction;

FIG. 7A is an exploded perspective view showing another embodiment ofthe fixing structure of a reinforcing member according to the presentembodiment;

FIG. 7B is a cross-sectional view showing a state in which thereinforcing member is coupled to a key portion of the oldham ring inFIG. 7A;

FIG. 8A is an exploded perspective view showing another embodiment ofthe fixing structure of a reinforcing member according to the presentembodiment;

FIG. 8B is a cross-sectional view showing a state in which thereinforcing member is coupled to a key portion of the oldham ring inFIG. 8A;

FIG. 9A is an exploded perspective view showing another embodiment ofthe fixing structure of a reinforcing member according to the presentembodiment;

FIG. 9B is a cross-sectional view showing a state in which thereinforcing member is coupled to a key portion of the oldham ring inFIG. 9A;

FIG. 10A is an exploded perspective view showing another embodiment ofthe fixing structure of a reinforcing member according to the presentembodiment;

FIG. 10B is a cross-sectional view showing a state in which thereinforcing member is coupled to a key portion of the oldham ring inFIG. 10A,

FIG. 11A is an exploded perspective view showing another embodiment ofthe fixing structure of a reinforcing member according to the presentembodiment;

FIG. 11B is a cross-sectional view showing a state in which thereinforcing member is coupled to a key portion of the oldham ring inFIG. 11A,

FIGS. 12A and 12B are perspective views from the front side and backside, respectively, of an oldham ring provided with an oil storage unitaccording to the present embodiment;

FIG. 13A is a cross-sectional view taken along line “IV-IV” in FIG. 12A;

FIG. 13B is a cross-sectional view showing another embodiment of the oilstorage unit according to FIG. 12A;

FIG. 14 is a plan view showing an oil storage unit according to thepresent embodiment;

FIG. 15 is a perspective view showing still another embodiment of theoil storage unit according to the present embodiment;

FIG. 16 is an enlarged cross-sectional view showing a state in which anoldham ring according to the present embodiment is assembled between aframe and a second scroll;

FIGS. 17A and 17B illustrate a plan view and a partially fracturedperspective view, respectively, showing an example in which an oilstorage unit according to the present embodiment is formed in a keygroove of a second scroll;

FIGS. 18 and 19 illustrate a perspective view and a cross-sectionalview, respectively, showing an example in which an oil storage memberaccording to the present embodiment is coupled to a key portion of theoldham ring;

FIGS. 20 and 21 are exploded perspective views showing a state in whicha key portion is separated from a ring portion to explain otherembodiments of an oldham ring in a motor-driven compressor according tothe present embodiment;

FIG. 22 is an exploded perspective view showing a reinforcing member ina key portion of an oldham ring according to the present embodiment; and

FIG. 23 is a fractured perspective view showing the key portion and thereinforcing member in a state in which the reinforcing member isassembled to the key portion of the oldham ring in FIG. 22.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, a scroll compressor according to the present disclosurewill be described in detail with reference to an embodiment illustratedin the accompanying drawings.

FIG. 1 is a cross-sectional view showing an inside of a motor-drivencompressor as an example of a scroll compressor according to the presentdisclosure, and FIG. 2 is a cross-sectional view showing a state inwhich an oldham ring is coupled between a frame and an orbiting scrollin a compression unit according to FIG. 1.

As illustrated in the drawings, the scroll compressor according to thepresent embodiment includes a drive motor 103, which is an electricmotor, and a compression unit 105 for compressing refrigerant using arotational force of the drive motor 103 within a compressor casing 101.

The compressor casing 101 is provided with an intake port 111 a to whicha suction pipe is connected and an exhaust port 121 a to which adischarge pipe is connected, and a suction space (S1) and a dischargespace (S2) are communicated with the suction port 111 a and thedischarge port 121 a, respectively. The drive motor 103 is installed inthe suction space (S1), and the compressor of the present embodimentforms a low pressure compressor.

Furthermore, the compressor casing 101 includes a main housing 110 inwhich the drive motor 103 is installed and a rear housing 120 coupled toan open rear end of the main housing 110. An inner space of the mainhousing 110 forms the suction space (S1) together with one side of thecompression unit 105, and an inner space of the rear housing 120 formsthe discharge space (S2). In the rear housing 120, the above-describedexhaust port 121 a is formed.

The main housing 110 may be formed with a cylindrical portion 111 formedin a cylindrical shape, and a front end of the cylindrical portion 111may be integrally extended to form a closed sealing portion 112, and aninverter module 200 may be coupled on a front side of the closed portion112. The rear end of the cylindrical portion 111 is open and the rearhousing 120 is sealed and coupled thereto.

On the other hand, a drive motor 103 constituting an electric motor unitis pressed and coupled to the main housing 110. The drive motor 103includes a stator 131 fixed inside the main housing 110 and a rotor 132positioned inside the stator 131 and rotated by an interaction betweenthe stator 131 and the rotor 132.

For the stator 131, a stator core (not shown) is shrink-fitted and fixedto an inner circumferential surface of the main housing 110. For therotor 132, a rotation shaft 133 is press-fitted to and coupled to aninner circumferential surface of a rotor core (not shown).

The rotation shaft 133 is coupled to the center of the rotor 132 suchthat a rear end facing the compression unit 105 is supported by theframe 140 and the fixed scroll 150, which will be described later, in acantilever manner.

On the other hand, the compression unit 105 includes a frame 140, afixed scroll (hereinafter, referred to as a first scroll) 150 supportedby the frame 140, and an orbiting scroll (hereinafter, referred to as asecond scroll) 160 disposed between the frame 140 and the first scroll150 to perform an orbiting movement.

The frame 140 is coupled to a front opening end of the main housing 110,and the first scroll 150 is fixedly supported on a rear side of theframe 140, and the second scroll 160 is orbitably supported by the rearside of the frame to perform an orbiting movement between the firstscroll 150 and the frame 140. Furthermore, the second scroll 160 iseccentrically coupled to the rotation shaft 133 coupled to the rotor 132of the drive motor 103 to form a pair of compression chambers (V) formedof a suction chamber, an intermediate pressure chamber, and a dischargechamber along with the first scroll 150 while performing an orbitingmovement with respect to the first scroll 150.

In addition, the frame 140 is formed with a frame end plate portion 141in a circular plate shape, and formed with a frame sidewall portion 142protruded from a rear side of the frame end plate portion 141 toward thefirst scroll 150 and coupled to a sidewall portion 152 of the firstscroll 150 which will be described later.

Furthermore, a frame thrust surface 143 on which the second scroll isplaced and supported in an axial direction is formed on an inner side ofthe frame sidewall portion 142, and a back pressure space 144 in whichpart of refrigerant compressed in the compression chamber (V) is filledalong with oil to support a back surface of the second scroll 160 isformed at the center of the frame thrust surface 143. Accordingly, apressure of the back pressure space 144 forms an intermediate pressurebetween the pressure of the suction space (S1) and a final pressure(i.e., the discharge pressure) of the compression chamber (V).

Furthermore, a frame shaft hole 145 through which the rotation shaft 133passes is formed at the center of the back pressure space 144, and afirst bearing (with no reference numeral) is provided on an innercircumferential surface of the frame shaft hole 145. The first bearingmay be made of a bush bearing, but in some cases, may be made of a ballbearing. However, the bush bearing is advantageous in terms of costsince it is less expensive than the ball bearing as well as advantageousdue to ease of assembly and reduced weight and noise.

A second key groove 146 into which a second key portion 176 of an oldhamring 170 which will be described later is slidably inserted is formed onan inner side of the frame thrust surface 143. Two second key grooves146 are typically formed at intervals of 180 degrees. The second keygroove will be described later together with a reinforcing member.

Meanwhile, the first scroll 150 may be fixedly coupled to the frame 140or may be press-fitted into the casing 110 to be fixed.

For the first scroll 150, a fixed scroll end plate portion (hereinafter,referred to as a fixed side end plate portion) 151 may be formed in asubstantially disk shape, and a fixed scroll sidewall portion(hereinafter, referred to as a first sidewall portion) 152 coupled to asidewall portion 142 of the frame 140 may be formed at an edge of thefixed side end plate portion 151. A fixed side wrap 153 engaged with anorbiting side wrap 162 which will be described later to form acompression chamber (V) is formed on a front surface of the fixed sidelongitudinal plate portion 151,

A suction passage (not shown) is formed at one side of the first sidewall portion 152 to allow the suction space (S1) and the suction chamber(not shown) to communicate with each other, and a discharge port 155communicated with the discharge chamber to discharge the compressedrefrigerant into the discharge space (S2) is formed at a central portionof the fixed side end plate portion 151.

Meanwhile, the second scroll 160 is provided between the frame (frame)and the first scroll 150, and eccentrically coupled to the rotationshaft 133 in an orbital manner.

For the second scroll 160, an orbiting scroll end plate portion(hereinafter, referred to as an orbiting side end plate portion) 161 isformed in a substantially disc shape, and an orbiting side wrap 162engaged with the fixed side wrap 153 to form a compression chamber isformed on a rear side of the orbiting side end plate portion 161. Theorbiting side wrap 162 may be formed in an involute shape together withthe fixed side wrap 153, but may be formed in various other shapes.

Furthermore, a scroll side thrust surface 165 that forms a thrustsurface together with respect to the frame side thrust surface 143 isformed on a front surface of the orbiting side end plate portion 161.However, since the second scroll 160 floats against the frame 140 whenthe compressor is driven, the frame side thrust surface 143 and thescroll side thrust surface 165 are substantially not in contact witheach other. Rather, the frame 140 and the second scroll 160 form athrust surface with the ring portion 171 of the oldham ring 170 which bedescribed later.

Furthermore, a first key groove 166 into which a first key portion 175of an oldham ring 170 which will be described later is slidably insertedis formed at the center of the scroll side thrust surface 165. Two firstkey grooves 166 are formed at intervals of 180 degrees. In the axialprojection, the first key groove 166 is formed with a phase differenceof about 90 degrees from the second key groove 146. The first key groovewill be described later together with a reinforcing member.

On the other hand, a rotation prevention mechanism for preventing arotational movement of the second scroll 160 is provided between theframe 140 and the second scroll 160. The rotation prevention mechanismmay be installed between the first scroll 150 and the second scroll 160according to circumstances. Hereinafter, an example in which therotation prevention mechanism is provided between the frame 140 and thesecond scroll 160 will be described as an example.

For the rotation prevention mechanism, a pin-and-ring type or an oldhamring type may be applicable thereto as described above. The presentembodiment relates to a case where the oldham ring type is appliedthereto.

The oldham ring 170 includes a ring portion 171 formed in an annularshape, and a plurality of first key portions 175 and a plurality ofsecond key portions 176 protruded from both side surfaces in the axialdirection of the ring portion 171. The structure of the oldham ring willbe described later together with the reinforcing member.

Reference numerals 137 and 152 denote a balance weight and areinforcement member, respectively.

The foregoing scroll compressor according to the present embodimentoperates as follows.

In other words, when power is applied to the drive motor 103, therotating shaft 133 transmits a rotational force to the second scroll 160while rotating together with the rotor 132, and the second scroll 160performs an orbiting movement by the oldham ring 170, which is arotation prevention mechanism, and the volume of the compression chamber(V) continuously decreases while moving toward the center side.

Then, refrigerant flows into the suction space (S1) through the intakeport 111 a and the refrigerant flowed into the suction space (S1) flowsthrough a passage formed on an outer circumferential surface of thestator 131 and an inner circumferential surface of the main housing 110,and a gap between the stator 131 and the rotor 132 and is sucked intothe compression chamber (V) through the suction passage 154.

At this time, part of the refrigerant sucked into the suction space (S1)through the intake port 111 a first comes into contact with the sealingportion 112, which is a front side of the main housing 110, prior topassing through the drive motor 103. Accordingly, the sealed portion 112is cooled by exchanging heat with cold suction refrigerant, therebydissipating heat of the inverter module 200 attached to the sealingportion 112 of the main housing 110.

On the other hand, refrigerant sucked into the compression chamber (V)through the suction space (S1) is compressed by the first scroll 150 andthe second scroll 160 and discharged into the discharge space (S2)through the discharge port 155, and the refrigerant discharged to thedischarge space (S2) is separated from the discharge space (S2), and therefrigerant is discharged to the refrigeration cycle through thedischarge port 121 a while oil is collected at a lower portion of thedischarge space (S2) and supplied to the respective bearing surfaces orto the compression chamber through an oil passage (not shown).

At this time, part of oil flows between the frame 140 and the secondscroll 160 to lubricate the oldham ring 170 and the frame 140 or thesecond scroll 160 coupled to the oldham ring 170.

On the other hand, the foregoing scroll compressor is widely applied notonly to air conditioning systems in buildings but also to airconditioning system in vehicles. Like other scroll compressors, scrollcompressors may reduce the weight of moving members to increasecompressor efficiency. In particular, when installed in a vehicle, it isadvantageous to reduce the weight of the compressor since the weight ofthe overall compressor as well as the rotating member is related to theweight of the vehicle.

Therefore, in a scroll compressor (typically, referred to as amotor-driven scroll compressor) applied to a vehicle, the oldham ring aswell as the casing, the frame, the fixed scroll and the orbiting scrollmay be made of a lightweight material such as aluminum (aluminum alloy).

However, as described above, when oldham ring and the frame or theorbiting scroll in contact with the oldham ring are formed of analuminum material, frictional characteristics according to the samematerial may be very poor, unlike cast iron.

Taking this into consideration, it is considered to form and assemblethe ring portion and the key portion of the oldham ring with differentmaterials or forming the whole oldham ring with the same material andthen forming a coating layer for improving the frictionalcharacteristics on a surface of the oldham ring. However, these methodshave limitations in machinability and reliability as described above.

Accordingly, an object of the present invention is to form the wholeoldham ring with the same material as to improve the machinability ofthe above-mentioned oldham ring as well as prevent the frictionalcharacteristics according to the same material from being deterioratedin advance while forming the frame or the orbiting scroll coupled to theoldham ring with the same material as that of the oldham ring, therebyensuring the reliability of the compressor.

FIG. 3 is an exploded perspective view showing the compression unitaccording to FIG. 2, and FIG. 4 is an exploded perspective view showinga state in which a reinforcing member is separated from an oldham ringin the compression unit according to FIG. 3, and FIG. 5 is a perspectiveview showing a state in which the reinforcing member is coupled to theoldham ring in FIG. 4, and FIG. 6 is a cross-sectional view showing astate in which the reinforcing member is coupled to the oldham ring andinserted into a key groove of an orbiting scroll in a radial direction.

As illustrated in the drawings, the frame 140, the second scroll 160,and the oldham ring 170 according to the present embodiment are allformed of an aluminum material that is lighter than cast iron. Thespecific gravity of cast iron is about 7.85, and the specific gravity ofaluminum alloy is about 2.8. Therefore, when the frame, the secondscroll, and the oldham ring are all formed of aluminum, the weight ofthe compressor may be greatly reduced.

The oldham ring 170 includes a ring portion 171 formed in an annularshape, and a first key portion 175 and a second key portion 176protruded from both side surfaces in the axial direction of the ringportion 171. The first key portion 175 is formed on one axial sidesurface of the ring portion 171, and the second key portion 176 isformed on the other axial side surface of the ring portion 171,respectively. The plurality of first key portions 175 and the second keyportions 176 are formed at intervals of 180 degrees along thecircumferential direction, and thus the first key portions 175 and thesecond key portions 176 are formed at intervals of 90 degrees withrespect to each other.

The first key portion 175 and the second key portion 176 arerespectively formed in a rectangular cross-sectional shape extended in aradial direction. However, the first key portion 175 and the second keyportion 176 may be formed in a shape having a square cross section or alength similar thereto according to circumstances. It will be describedagain later together with the key groove.

The ring portion 171 and the key portions 175, 176 are formed as asingle body. In other words, the first key portion 175 and the secondkey portion 176 are extended integrally from the ring portion 171.Accordingly, the ring portion 171 and the key portions 175, 176 may beformed of the same material, and in other words, the whole oldham ringmay be formed of an aluminum material.

On the other hand, a plurality of first key grooves 166 corresponding tothe first key portion 175 of the oldham ring 170 and a plurality ofsecond key grooves 146 corresponding to the second key portion 176 ofthe oldham ring 170 are respectively formed on the second scroll 160 andthe frame 140. The plurality of first key grooves 166 and second keygrooves 146 are formed on surfaces facing each other.

The first key groove 166 of the second scroll 160 and the second keygroove 146 of the frame 140 are formed to have a sufficiently largerlength in a radial direction, and formed to have a width substantiallyin contact with the side surfaces of the first key portion 175 and thesecond key portion 176 in a circumferential direction compared to thefirst key portion 175 and the second key portion 176 of the oldham ring.

Accordingly, the first key portion 175 and the second key portion 176 ofthe oldham ring 170 may transmit a force in a circumferential directionwhile sliding in a radial direction with respect to the first key groove166 of the second scroll 160 and the second key groove 146 of the frame140.

Therefore, according to the present embodiment, the reinforcing members180, 180 may be inserted between a circumferential side surface of thefirst key groove 166 and a circumferential side surface of the first keyportion 175, and between a circumferential side surface of the secondkey groove 146 and a circumferential side surface of the second keyportion 176. In other words, the reinforcing members 180, 180 may beinserted into and fixed to the inner surfaces of the first key groove166 and the second key groove 146, but may also be inserted into andfixed to an outer surface of the first key portion 175 and the secondkey portion 146 as illustrated in the present embodiment.

The reinforcing members 180, 180 according to the present embodiment maybe preferably formed of a material having a higher rigidity than thesecond scroll 160 or the frame 140 or the oldham ring 170, that is amaterial different from that of the second scroll 160 or the frame 140or the oldham ring 170. Accordingly, when the first key portion 175 andthe second key portion 176 perform a sliding movement with respect tothe first key groove 166 and the second key groove 146, respectively, itmay possible to prevent the key portion from being directly brought intocontact with the key groove, which is the same material. As a result, itmay be possible to suppress the key portion of the second scroll 160 orthe key groove of the frame 140 or the key portion of the oldham ring170 from being worn out though the second scroll 160, the frame 140, orthe oldham ring 170 are all made of a light material.

Hereinafter, the reinforcing member and the key groove into which thereinforcing member is inserted will be described in detail. The firstkey groove, the first key portion, and the reinforcing member providedtherebetween are the same as the second key groove, the second keyportion, and the reinforcing member provided therebetween, respectively.Therefore, the first key groove, the first key portion, and thereinforcing member inserted between the first key groove and the firstkey portion will be mainly described.

Referring again to FIGS. 3 and 4, the first key portion 175 has a largerradial length than a circumferential (or tangential) length. Here, bothside surfaces in a radial direction are defined as an outercircumferential side surface 175 a and an inner circumferential sidesurface 175 b, and both side surfaces in a circumferential direction aredefined as a sliding side surface 175 c. Accordingly, the first keyportion 175 according to the present embodiment is formed such that alength between the outer circumferential side surface 175 a and theinner circumferential side surface 175 b is larger than a length betweenthe both sliding side surfaces 175 c. However, the present invention isnot limited thereto, and the two lengths may be the same or formed in anopposite manner so that the length between side surfaces 175 a and 175 bis smaller than the length between side surfaces 175 c.

The first key portion 175 according to the present embodiment is formedsuch that the outer circumferential side surface 175 a and both thesliding side surfaces 175 c are formed in a flat shape, and the innercircumferential side surface 175 b is formed with a release preventinggroove 175 b 1 such that the release preventing portions 185 a, 185 b ofthe reinforcing member 180 a are inserted and hooked.

The release preventing groove 175 b 1 may be formed in a groove shaperecessed by a predetermined depth in a central portion of the innercircumferential side surface 175 b as shown in FIGS. 4 through 6. Inother words, the release preventing groove 175 b 1 is formed lower thanboth the sliding side surfaces 175 c around the release preventinggroove 175 b, while at the same time being formed lower than an axialside surface on a back side of the ring portion 171. Accordingly, therelease preventing groove 175 b 1 may be formed in a shape in which boththe axial side surface and the circumferential side surface are blocked.

Furthermore, the release preventing groove 175 b 1 may be formed in arectangular cross-sectional shape when projecting on the innercircumferential surface side, or may be formed in a circularcross-sectional shape according to circumstances. However, in the caseof a circular cross-sectional shape, it may be advantageous when anaxial width of the reinforcing member which will be described later issmall, or when an axial width of the preventing portion is small in thereinforcing member. When an axial width of the reinforcing member 180 islarge, it is advantageous that the release preventing groove 175 b 1 isformed in a rectangular cross-sectional shape.

Furthermore, the radial cross-sectional area of the release preventinggroove 175 b 1 may be preferably formed to be larger than the entirecross-sectional area in the longitudinal direction of the releasepreventing portions 185 a, 185 b of the reinforcing member 180 insertedinto the release preventing groove 175 b 1. For example, as shown inFIGS. 5 and 6, and in a radial direction on an inner circumferentialsurface of the oldham ring 170, when both the release preventingportions 185 a, 185 b of the first reinforcing member 180 a are insertedinto and engaged with the release prevention groove 175 b 1, an area ofthe release preventing groove 175 b 1 may be formed to be wide enough toprovide a space between both the release preventing portions 185 a, 185b. Then, a vacant space of the release preventing groove 175 b 1 formedbetween both the release preventing portions 185 a, 185 b may serve as atype of oil storage groove so that oil flowing into the first key groove166 can be contained in the release preventing groove 175 b 1. Then,when the compressor is driven, the oil contained in the vacant space ofthe release preventing groove 175 b 1 may lubricate between the keygroove and the key portion, and may store the oil when the driving isstopped.

Meanwhile, a first reinforcing member 180 a according to the presentembodiment may be formed by bending a metal plate or molding a polymermaterial. Since the first reinforcing member 180 a should be fixed whilebeing inserted into an outer surface of the first key portion 175, thefirst reinforcing member 180 a preferably has a predeterminedelasticity. For this purpose, the first reinforcing member 180 a may beformed to have a smaller width at an end portion of the fixing surfaces183 a, 183 b compared to an end portion of the first reinforcing member180 a, which will be described later, in the pre-assembly state. Then,the fixing surfaces 183 a, 183 b may be spread to both sides andinserted into the first key portion 175 so that both the fixing surfaces183 a, 183 b can be securely fixed to the first key portion 175 whilebeing shrunk by restoring force.

As shown in FIG. 4, the first reinforcing member 180 a according to thepresent embodiment includes a first reinforcing surface 181 a, a secondreinforcing surface 181 b, a connecting surface 182, a first fixingsurface 183 a, and a second fixing surface 183 b.

The first reinforcing surface 181 a and the second reinforcing surface181 b are arranged in parallel to each other in a radial direction andformed to surround both sliding sides of the first key portion 175. Theconnecting surface 182 is formed to surround the outer circumferentialside surface 175 a of the first key portion 175 by connecting one end ofthe first reinforcing surface 181 a and one end of the secondreinforcing surface 181 b. The fixing surfaces 183 a, 183 b are extendedfrom the other end of the first reinforcing surface 181 a and the otherend of the second reinforcing surface 181 b, respectively, which areopposite to the connecting surface 182 to surround the innercircumferential surface 175 b of the first key portion 175.

The first reinforcing surface 181 a and the second reinforcing surface181 b are formed to be flat and closely attached to both sliding sidesurfaces 175 c, 175 c of the first key portion 175, and an outer surfaceof the first reinforcing surface 181 a and an outer surface of thesecond reinforcing surface 181 b may be disposed on both circumferentialsurfaces of the first key groove 166 with a predetermined lubricationspace to face each other.

The connecting surface 182 may be closely attached to the outercircumferential surface 175 a of the first key portion 175 as describedabove. However, in some cases, it may be closely attached to the innercircumferential side surface 175 b of the first key portion 175. In thiscase, the release preventing groove 175 b 1 is formed on the outerperipheral side surface 175 a of the first key portion 175.

The first fixing surface 183 a and the second fixing surface 183 b arebent in a direction toward the second reinforcing surface 181 b from theother end of the first reinforcing surface 181 a and in a directiontoward the first reinforcing surface 181 a from the other end of thesecond reinforcing surface 181 b, respectively. The first fixing surface183 a and the second fixing surface 183 b may be closely attached andfixed to the inner circumferential side surface 175 b of the first keyportion 175, respectively.

Moreover, a first release preventing portion 185 a and a second releasepreventing portion 185 b, which are bent toward the release preventinggroove 175 b 1, may be bent at an end portion of the first fixingsurface 183 a and an end portion of the second fixing surface 183 b. Thefirst release preventing portion 185 a and the second release preventingportion 185 b may be inserted from both the transverse sides of therelease preventing groove 175 b 1 and fixed thereto in an engagingmanner in the axial direction. As described above, a vacant space isformed between the first release preventing portion 185 a and the secondrelease preventing portion 185 b by a predetermined distance, and thevacant space forms the above-described oil storage groove.

Meanwhile, as described above, the second key groove 146 may be formedin the frame 140 to slidably insert the second key portion 176 of theoldham ring 170 thereinto. The reinforcement member 180 b may be coupledto the second key portion 176, and the release preventing groove and therelease preventing portion may be formed on the second key portion 176and the reinforcement member 180 b, respectively.

Referring again to FIG. 2, the second key groove 146 of the frame 140and the second key portion 176 of the oldham ring 170 may also be formedto have the same shape as those of the first key portion 166 of thesecond scroll 160 and the first key portion 175 of the oldham ring 170as described above.

However, the second reinforcing member 180 b inserted between the secondkey groove 146 and the second key portion 176 and between the second keygroove 146 and the second key portion 176 is formed by the first keygroove 166 has an inner direction and an outer direction opposite toeach other, but has the same shape, when compared to the firstreinforcing member 180 a inserted between the first key portion 166 andthe first key portion 175.

Furthermore, the shape of the second reinforcing member 180 b and theshape of the release preventing portion including the release preventinggroove for preventing the second reinforcing member 180 b from beingreleased are also the same as those of the above-described embodiments.Therefore, the detailed description thereof will be substituted by thedescription of the first key portion and the reinforcing member coupledto the first key portion.

The foregoing scroll compressor according to the present embodiment hasthe following operational effects.

In other words, as the first and second reinforcing members 180 a, 180 bare inserted between the first key groove 166 and the first key portion175 and between the second key groove 146 and the second key portion176, it may be possible to prevent the first key portion 175 of theoldham ring 170 and the second key portion 176 of the oldham ring 170from being directly brought into contact with the first key groove 166of the second scroll 160 and the second key groove 146 of the frame 140,respectively.

Accordingly, even when the second scroll 160, the frame 140, and theoldham ring 170 are all formed of the same material, particularly analuminum material having a hardness lower than that of cast iron, it maybe possible to suppress frictional characteristics between the oldhamring 170 and the frame 140 from being deteriorated, thereby improvingthe reliability of the compressor.

In addition, as the second scroll 160, the frame 140, and the oldhamring 170 are all formed of a lightweight aluminum material, the weightof the compressor may be reduced, thereby enhancing the efficiency ofthe compressor as well as the efficiency of a device such as a vehicleto which the compressor is applied.

In addition, as the ring portion 171 and the key portions 175, 176 ofthe oldham ring 170 may be formed as a single body, thereby sufficientlyreinforcing a connection portion between the ring portion and the keyportion. Accordingly, it may be possible to suppress a connectionportion between the ring portion 171 and the key portions 175, 176 frombeing damaged by receiving a force, thereby improving the reliability ofthe compressor.

In addition, as the ring portion 171 and the key portions 175, 176 ofthe oldham ring 170 are formed as a single body, a machining errorbetween the ring portion 171 and the key portions 175, 176 or adeformation of the key portions 175, 176 may be minimized. Accordingly,when the compressor is driven, the key portion being twisted from thekey groove in an undesired direction may be minimized, therebysuppressing a compression loss due to a gap between the wraps.

In addition, it may not be required to form an additional coating layeron a surface of the oldham ring 170, thereby reducing the fabricationcost of the oldham ring 170 and suppressing the damage of the oldhamring or a friction loss due to peeling of the coating layer.

In addition, in the foregoing embodiment, the release preventing groovesmay form a type of oil storage space. Then, a predetermined amount ofoil may be stored during operation and stop of the compressor, and thestored oil may flow and lubricate between the key groove and the keyportion, more precisely, between the key portion and the reinforcingmember. Then, the wear-out of the key portion may be suppressed moreeffectively.

Meanwhile, another embodiment of a structure of fixing the reinforcingmember according to the present disclosure will be described as follows.

In other words, in the above-described embodiment, the releasepreventing groove is formed in a shape that is closed in an axialdirection, but in the present embodiment, the release preventing grooveis formed in a shape that is open in an axial direction. FIG. 7A is anexploded perspective view showing another embodiment of the fixingstructure of a reinforcing member according to the present embodiment,and FIG. 7B is a cross-sectional view showing a state in which thereinforcing member is coupled to a key portion of the oldham ring inFIG. 7A.

As illustrated in the drawings, the release preventing groove 275 b 1according to the present embodiment may be formed on an innercircumferential side surface 275 b of the first key portion 275, butextended by a predetermined length along an axial direction on one axialside surface thereof. As a result, the release preventing groove 275 b 1has a closed shape on both sides in the circumferential direction, buthas an open shape on one axial side surface on the back side of the ringportion 171.

In this case, the reinforcing member 280 may be extended by bending therelease preventing portions 285 a, 285 b from both the fixing surfaces283 a, 283 b toward the connecting surface 282 as in the foregoingembodiment. Other configurations of the reinforcing member 280 may beformed in the same manner as in the foregoing embodiment.

As described above, as the release preventing groove 275 b 1 is formedin a shape in which one axial side surface 275 b 2 is open on an innercircumferential side surface 275 b of the first key portion 166, thereinforcing member 280 may be easily connected to the first key portion275. In other words, in the foregoing embodiment, as the releasepreventing groove 175 b 1 is formed in a closed shape in the axialdirection as well as the circumferential direction on the innercircumferential side surface 175 b of the first key portion 175, whenthe reinforcing member 180 is assembled, it is not easy to fit therelease preventing portions 185 a,185 b into the release preventinggroove 175 b 1 since both of the reinforcing surfaces 181 a, 181 b mustbe spread and inserted into the first key portion 175. However, when oneaxial side surface of the release preventing groove 275 b 1 is formed inan open shape as in the present embodiment, the reinforcing member 280may be assembled by pushing it in the axial direction, and thus therelease preventing portions 285 a, 285 b may be easily assembled intothe release preventing groove 275 b 1.

Meanwhile, still another embodiment of a structure of fixing thereinforcing member according to the present disclosure will be describedas follows.

In other words, in the foregoing embodiments, both circumferential sidesurfaces of the release preventing groove are formed in a closed shape,but in the present embodiment, both circumferential side surfaces of therelease preventing groove are formed in an open shape. FIG. 8A is anexploded perspective view showing another embodiment of the fixingstructure of a reinforcing member according to the present embodiment,and FIG. 8B is a cross-sectional view showing a state in which thereinforcing member is coupled to a key portion of the oldham ring inFIG. 8A.

As illustrated in the drawings, the release preventing groove 375 b 1according to the present embodiment is formed in a closed shape on oneaxial side surface on a back side of the ring portion 371, and formed inan open shape on both circumferential side surfaces thereof.Accordingly, an engaging surface 375 b 2 is formed on one axial sidesurface of the release preventing groove 375 b 1, and thus thereinforcing member 380 may be axially supported by the ring portion 371and the engaging surface 375 b 2.

In this case, the reinforcement member 380 may not be formed with therelease preventing portion in a different manner from the foregoingembodiments. In other words, as both the fixing surfaces 383 a, 383 b ofthe reinforcing member 380 are inserted into and closely attached to therelease preventing groove 375 b, the reinforcement member 380 may befirmly fixed to the first key portion 375 without forming an additionalrelease preventing portion on the reinforcing member 380.

As described above, when both circumferential side surfaces of therelease preventing groove 375 b 1 are formed in an open shape, it maynot be required to bend an additional release preventing portion on thereinforcing member, thereby simplifying the fabrication of thereinforcing member 380 and facilitating the assembly.

Moreover, when a depth of the release preventing groove 375 b 1 isformed to be equal to or greater than a thickness of the reinforcingmember 380, the fixing surface 385 b 2 of the reinforcing member 380 maybe completely embedded in the key portion 375. Accordingly, it may notbe required to reduce a length of the key portion 375 in considerationof the reinforcing member 380, and a sliding area between the keyportions 375, 376 and the key grooves 166, 146 may be ensured to preventan outer diameter of the second scroll or the frame from being enlargedin advance, which is advantageous for downsizing of the compressor.

Although not illustrated in the drawings, a groove may be formed in acircumferential direction (transverse direction) on an innercircumferential side surface or an outer circumferential side surface ofthe key portion in the foregoing other embodiments or embodiments to bedescribed later. Then, as described above, the reinforcement member maybe embedded in the key portion to secure a sliding area between the keyportion and the key groove without increasing a length of the keyportion.

Meanwhile, still another embodiment of a structure of fixing thereinforcing member according to the present disclosure will be describedas follows.

In other words, in the above-described embodiments, the fixing surfacesare provided at both ends of the reinforcing member and axially attachedto an inner circumferential side surface or an outer circumferentialside surface of the key portion, but in the present embodiment, both thereinforcing surfaces and the connecting surface are fixed to the keyportion without using the fixing surfaces. FIG. 9A is an explodedperspective view showing another embodiment of the fixing structure of areinforcing member according to the present embodiment, and FIG. 9B is across-sectional view showing a state in which the reinforcing member iscoupled to a key portion of the oldham ring in FIG. 9A.

As illustrated in the drawings, the reinforcing member 480 according tothe present embodiment includes a first reinforcing surface 481 a and asecond reinforcing surface 481 b, and a connecting surface 482 formedbetween the first reinforcing surface 481 a and the second reinforcingsurface 481 b to surround an outer surface of the first key portion 475.

A gap between the first reinforcing surface 481 a and the secondreinforcing surface 481 b may be formed to be narrower toward anopposite end with respect to the connecting surface 482. Accordingly,when the reinforcement member 480 is inserted into the first key portion475, an opening end between the first reinforcement surface 481 a andthe second reinforcement surface 481 b that have been spread may beclosely attached and fixed to both circumferential side surfaces of thefirst key portion 475 while being elastically restored.

In this case, the reinforcing member 480 is formed with the releasepreventing portions 485 a, 485 b to prevent the reinforcement member 480from being released, and the release preventing grooves 475 c 1, 475 c 1into which the release preventing portions 485 a, 485 b are inserted maybe respectively formed on both the sliding surfaces 475 a, 475 b of thefirst key portion 475 facing the release preventing portions 485 a, 485b.

The release preventing portions 485 a, 485 b may be formed in aprotruding shape protruded toward the first key portion 475, and therelease preventing grooves 475 c 1, 475 c 1 may be formed in a shapecorresponding to that of the release preventing portions 485 a, 485 b.

The release preventing portions 485 a, 485 b may be formed on the firstreinforcing surface 481 a and the second reinforcing surface 481 brespectively, but may also be formed on only one of the reinforcingsurfaces or on the connecting surface 482.

As described above, when the fixing surface is not formed on thereinforcing member 480, and the reinforcement member 480 is fixed to thekey portion 475 only by an elastic force of the reinforcing surfaces 481a or the release preventing portions 481 b, 485 b having a protrusionshape are formed on the protruding surfaces 481 a, 481 b, thereinforcing member 480 and the key portion 475 may be easily fabricatedand assembled. Moreover, a sliding area between the key portion 475 andthe key groove 166 can be secured without enlarging the length of thekey portion 475, which is advantageous for downsizing of the compressor.

Meanwhile, still another embodiment of a structure of fixing thereinforcing member according to the present disclosure will be describedas follows.

In other words, in the foregoing embodiments, one reinforcing member isinserted into and coupled to one key portion, but in the presentembodiment, a plurality of reinforcing members are inserted into andcoupled to one key portion. FIG. 10A is an exploded perspective viewshowing another embodiment of the fixing structure of a reinforcingmember according to the present embodiment, and FIG. 10B is across-sectional view showing a state in which the reinforcing member iscoupled to a key portion of the oldham ring in FIG. 10A.

As illustrated in the drawings, a plurality of reinforcing members 580according to the present embodiment may be provided and coupled to bothcircumferential side surfaces of the first key portion 575. In thiscase, the first key portion 575 is provided with the release preventinggrooves 575 a 1, 475 b 1 on the outer circumferential side surface 575 aand the inner circumferential side surface 475 b, respectively, and therelease preventing portions 585 a, 585 a of each reinforcing member 580may be respectively inserted into and fixed to the release preventinggrooves 575 a 1, 575 b 1.

The reinforcing member 580 may be formed by bending the fixing surfaces583 a, 583 b at both radial ends of the first reinforcing surface 581 aor the second reinforcing surface 581 b in a different manner from theforegoing embodiments, and the release preventing portions 585 a, 585 bmay be bent in a radial direction in directions facing the releasepreventing grooves 575 a 1, 575 b 1, respectively, at both end portionsof the fixing surfaces 583 a, 583 b. The release preventing portions 585a, 585 b may be inserted into and fixed to the release preventinggrooves 575 a 1, 575 b 1.

Here, the release preventing grooves 575 a 1, 575 b 1 may be formed atthe center of the outer circumferential side 575 a and the innercircumferential side 575 b of the first key portion 575 as illustratedin the present embodiment, but may also be formed into an axially openshape as illustrated in the embodiment of FIG. 7 according tocircumstances. Furthermore, as illustrated in the embodiment of FIG. 9A,protrusions and grooves may be formed on the reinforcing surfaces andthe sliding surfaces, respectively, to prevent the reinforcing memberfrom being released, and as illustrated in the embodiment of FIG. 11A,the reinforcing member may be fixed to the key portion by an elasticforce of the first fixing surface 583 a and the second fixing surface583 b. These embodiments are the same as the above-describedembodiments, and thus the description thereof will be omitted.

As described above, when the reinforcing member is formed with aplurality of reinforcing members 580, the lengths of the first andsecond fixing surfaces 583 a, 583 b constituting an elastic surface ofeach reinforcing member 580 may be shortened, thereby facilitating theassembly.

Moreover, the first reinforcing surface 581 a and the second reinforcingsurface 581 b constituting a sliding surface are formed in parallel toconnect the first fixing surface 583 a and the second fixing surface 583b, respectively. Accordingly, the first reinforcing surface 581 a andthe second reinforcing surface 581 b may be closely attached to bothcircumferential side surfaces of the first key portion 575 even if amachining error occurs in the reinforcing member 580, thereby preventinga friction loss to the key groove in advance.

Meanwhile, still another embodiment of a structure of fixing thereinforcing member according to the present disclosure will be describedas follows.

In other words, in the above-described embodiments, even when the fixingsurface is excluded from the reinforcing member, the assembly directionof the reinforcing member is assembled in a radial direction, that is,allowing the connecting surface to be closely attached to an outercircumferential side surface of the first key portion, but in thepresent embodiment, the assembly direction of the reinforcing member isformed in an axial direction, that is, allowing the connecting surfaceto be closely attached to an axial side surface of the first keyportion. FIG. 11A is an exploded perspective view showing anotherembodiment of the fixing structure of a reinforcing member according tothe present embodiment, and FIG. 11B is a cross-sectional view showing astate in which the reinforcing member is coupled to a key portion of theoldham ring in FIG. 11A.

As illustrated in the drawings, the reinforcing member 680 according tothe present embodiment includes a first reinforcing surface 681 a and asecond reinforcing surface 681 b, and a connecting surface 682 forconnecting the first reinforcing surface 681 a and the secondreinforcing surface 681 b.

The first reinforcing surface 681 a and the second reinforcing surface681 b are closely attached and fixed to both sliding surfaces 675 c, 675c of the first key portion 675, and the connecting surface 682 isclosely attached and fixed to an axial side surface 675 d of the firstkey portion 675.

Moreover, even in this case, the first reinforcing surface 681 a and thesecond reinforcing surface 681 b, which are bent and extended from bothends of the connecting surface 682 may be formed to be narrower towardan opposite side of the connecting surface 682. Then, the reinforcingmember 680 may be firmly fixed by an elastic force in a state where thereinforcing member 680 is inserted into the first key portion 675.

Moreover, even in this case, the first reinforcing surface 681 a and thesecond reinforcing surface 681 b of the reinforcing member 680 may beformed with protrusions constituting the release preventing portions 685a, 685 b, respectively, although not shown in the drawing, and therelease preventing grooves 650 c 1, 675 c 1 with grooves may be formedon both circumferential side surfaces of the first key portion 675facing the respective reinforcing surfaces 681 a,681 b to receive theprojections.

The operational effects of this embodiment is similar to that of theforegoing embodiment, and therefore, the description thereof will beomitted. However, the present embodiment is easier to assemble as theinsertion length is shorter than that of the foregoing embodiment.Furthermore, as the connecting surface 682 of the reinforcing member 680according to the present embodiment surrounds an axial side surface ofthe first key portion 675, it may be possible to suppress wear-out on anaxial side surface of the key portion caused by an assembly error or anunstable behavior of the second scroll during operation.

On the other hand, in the present embodiment, an example in which theoldham ring is provided between the frame and the orbiting scroll andslidably coupled to the frame and the second scroll has been described,but the oldham ring may be slidably coupled to a key groove provided inthe fixed scroll and a key groove provided in the orbiting scroll,respectively, between the fixed scroll and the orbiting scroll. Even inthis case, the reinforcing members described above may be respectivelycoupled to the first key portion and the second key portion of theoldham ring.

In addition, although a motor-driven scroll compressor in which thecasing is installed in a transverse direction has been described in theabove-mentioned embodiments, the present disclosure may also beapplicable to a general scroll in which the casing is installed in alongitudinal direction.

On the other hand, refrigerant sucked into the compression chamber (V)through the suction space (S1) is compressed by the first scroll 150 andthe second scroll 160 and discharged into the discharge space (S2)through the discharge port 155, and the refrigerant discharged to thedischarge space (S2) is separated from the discharge space (S2), and therefrigerant is discharged to the refrigeration cycle through thedischarge port 121 a while oil is collected at a lower portion of thedischarge space (S2) and supplied to the respective bearing surfaces orto the compression chamber through an oil passage (not shown).

At this time, part of oil flows between the frame 140 and the secondscroll 160 to lubricate the oldham ring 170 and the frame 140 or thesecond scroll 160 coupled to the oldham ring 170.

However, as described above, in a motor-driven compressor installed in atransverse type, the rotation shaft 133 is installed in a horizontaldirection or in a similar form thereto, and thus the frame 140 and thesecond scroll 160 coupled to the rotating shaft 133 are also arranged ina direction parallel to the ground. Then, oil that has been suppliedbetween the frame 140 and the second scroll 160 during the operation ofthe compressor to lubricate the oldham ring 170 is poured in a downwarddirection when the compressor is stopped, there is insufficient oil oralmost no oil when the stop time of the compressor becomes long. Whenthe compressor is restarted in this state, the oldham ring 170 performsa relative movement with respect to the frame 140 or the second scroll160 in an oil insufficient state, which causes a friction loss orwear-out in the oldham ring 170 or cause damage such as breakage of avulnerable portion such as a portion where the ring portion 171 isbrought into contacts with the key portion 175 in a severe case.

Accordingly, in the present invention, oil may be supplied to the oldhamring and a portion where the oldham ring comes into contact therewithwhile restarting the compressor, thereby providing an oil storage unitcapable of suppressing friction loss, wear-out or damage of parts due tooil shortage, particularly, in a transverse type compressor.

FIGS. 12A and 12B are perspective views in which an oldham ring providedwith an oil storage unit according to the present embodiment is seenfrom both sides, FIG. 13A is a cross-sectional view taken along line“IV-IV” in FIG. 12A, FIG. 13B is a cross-sectional view showing anotherembodiment of the oil storage unit is according to FIG. 12A, FIG. 14 isa plan view showing an oil storage unit according to the presentembodiment, and FIG. 15 is a perspective view showing still anotherembodiment of the oil storage unit according to the present embodiment.As illustrated in the drawings, the oldham ring according to the presentembodiment may be provided with an oil storage unit capable of storingoil.

For example, the oldham ring 170 according to the present embodiment maybe formed entirely of a material such as aluminum to reduce the weight,or a portion where friction is not generated, such as the ring portion171, may be formed of aluminum, whereas the key portion 175 insertedinto the key groove (not shown) of the frame 140 or the key groove 166of the second scroll 160 to perform a sliding movement may be formed ofa material having higher strength than aluminum.

To this end, the key portion 175 formed in a piece may be inserted intoand coupled to the ring portion 171 formed in a ring shape along acircumferential direction, or both the ring portion 171 and the keyportion 175 may be made of aluminum, and then coated with a wearresistant material. Here, when the key portion 175 is inserted into thering portion 171, the protrusions and the grooves may be formed in anangular shape or a rectangular shape to prevent the key portion 175 fromrotating with respect to the ring portion 171.

On the other hand, the oil storage unit 175 d may be formed in each ofthe key portions 175, respectively. Accordingly, while restarting thecompressor, oil stored in the oil storage unit 175 d may quickly wet thekey portion 175 to lubricate the key portion 175 and the key groove 166brought into contact therewith.

The oil storage unit 175 d may be formed in a groove shape having apredetermined depth to carry oil. When the oil storage unit 175 d isformed with a groove, a structure in which a side facing the ground,that is, a lower side, is formed in a closed shape in consideration ofthe fact that the compressor is installed in a transverse type, and anopen end of the oil storage unit 175 d is formed toward an opposite sideto the ground, that is, an upper side, may be suitable to carry oil.However, an opening end direction of the oil storage unit 175 d does notnecessarily have to be directed to an opposite side to the ground, butmay also be formed at an oblique inclination. However, even when the oilstorage unit 175 d is formed to be inclined, an opening end of the oilstorage unit should be formed to be positioned higher than the closedend.

In addition, the oil storage unit 175 d may be preferably formed to havethe same cross-sectional area along the longitudinal direction duringmachining, but a closed lower end thereof may be wide or may be formedto be wider toward the lower end in some cases. Of course, on thecontrary, an upper end thereof may be wide or may be formed to be widertoward the upper end. When an upper end of the oil storage unit 175 d iswide, it may be possible to compensate to some extent that the strengthof the key portion is weakened due to the oil storage unit. In otherwords, the key portion 175 is extended and protruded from a side surfaceof the ring portion 171, and thus the key root portion where the keyportion 175 starts to protrude from the ring portion 171 may beweakened. In order to prevent the root portion from being weakened, itmay be preferable to form the oil storage unit 175 d narrowly or to formshallowly even when the oil storage unit 175 d is formed wide.Hereinafter, the key portion 175 inserted into the key groove 166 of thesecond scroll among the plurality of key portions will be described, butthe other key portions are the same.

For example, as shown in FIG. 13A, the oil storage unit 175 d may beformed so as to be positioned outside the key root portion 175 e, thatis, away from the ring portion 171 so as not to overlap with the keyroot portion 175 e. As a result, a cross-sectional area of the key rootportion 175 e excluding the oil storage unit 175 d is reduced to preventthe strength of the key root portion from being weakened. However, insome cases, the oil storage unit 175 d may be formed to overlap with thekey root portion 175 e. In this case, as shown in FIG. 4B, a depth (H1)of the oil storage unit 175 d may be preferably set to be ½ or less thana height (H2) of the key portion 175 to maintain the strength of the keyroot portion 175 e.

Furthermore, as shown in FIG. 14, an axial cross-sectional area (A) ofthe oil storage unit 175 d may be formed to be smaller than or equal tothat of the key portion 175 excluding the ring portion 171, that is, anaxial cross-sectional area (A2) from the key root portion 175 e to anouter end thereof. Accordingly, it may be possible to prevent an overallcross-sectional area (A2) of the key portion 175 from being reduced aswell as prevent the strength of the key portion 175 including the keyroot portion 175 e from being weakened due to the oil storage unit 175d. These axial directions are directions based on the rotation shaft.

However, in some cases, an axial cross-sectional area (A1) of the oilstorage unit 175 d may be formed to be larger than the axialcross-sectional area (A2) of the key portion 175 excluding the ringportion. In this case, as shown in FIG. 15, the oil storage unit 175 dmay be formed with a plurality of grooves to sufficiently secure anaxial cross-sectional area of the key portion 175 excluding the oilstorage unit 175 d. As a result, the reduction of the strength of thekey portion 175 may be minimized while the oil storage unit 175 d isformed with a plurality of grooves. At this time, each of the groovesforming the oil storage unit 175 d may be formed to be smaller than thatof the oil storage unit having one groove as described above.

Of course, even when the axial cross-sectional area (A1) of the oilstorage unit 175 d may be formed to be smaller than or equal to theaxial cross-sectional area (A2) of the key portion 175 excluding thering portion, the oil storage unit 175 d may be formed with a pluralityof grooves.

The operational effects of the oldham ring provided with an oil storageunit according to the present embodiment are as follows. FIG. 16 is anenlarged cross-sectional view showing a state in which an oldham ringaccording to the present embodiment is assembled between a frame and asecond scroll.

In other words, when the compressor performs a normal operation, part ofoil flowing into the compression chamber (V) or the back pressure space144 flows between the frame 140 and the second scroll 160 as describedabove, and the oil flows between the key groove 166 of the second scroll160 and the key portion 175 of the oldham ring 170 and between the keygroove 146 of the frame 140 and the key portion 175 of the oldham ringto lubricate between the respective key grooves and key portions.

On the contrary, when the compressor is stopped, most of oil filledbetween the respective key grooves 146, 166 and key portions 175 flowsout due to its own weight and is accumulated at a lower portion of thecompressor casing 101. In this case, oil shortage may occur between therespective key grooves and key portions while restarting the compressor.

In this embodiment, however, as grooves forming the oil storage unit 175d are formed in the key portion 175 of the oldham ring 170, part of oilflowing between the respective key grooves 146 and the key portions 175during the operation of the compressor is filled and carried in the oilstorage unit 175 d, and the oil is maintained without getting out evenwhen the compressor is stopped.

Then, while restarting the compressor, oil filled in the respective theoil storage units 175 d flows out to lubricate between the respectivekey grooves 146, 166 and the key portions 175, thereby preventing oilshortage from occurring between the frame 140 and the oldham ring 170 orbetween the second scroll 160 and the oldham ring 170 in advance.

In a motor-driven compressor according to the present invention, anotherembodiment of the oil storage unit will be described as follows.

In other words, in the foregoing embodiment, the oil storage unit may beformed in the oldham ring, but the oil storage unit may also be providedin the frame or the second scroll in contact with the oldham ring. FIGS.17A and 17B are a plan view and a partially fractured perspective viewshowing an example in which an oil storage unit according to the presentembodiment is formed in a key groove of a second scroll.

As illustrated in the drawings, the oil storage unit 167 may be formedon both sides of the key groove 166 of the second scroll 160perpendicular to the sliding direction of the key portion 175. The oilstorage unit 167 may be formed in a structure in which both longitudinalends thereof are closed, but in some cases, the oil storage unit 167 maybe formed in a structure in which at least either one of them is open.It is a structure when the key groove 166 of the second scroll 160 ispositioned in a direction parallel to the ground.

As described above, even when the oil storage unit 167 is formed in thekey groove 166, the same effect as that described above may be expected.In other words, when the oil storage unit 167 is formed in the keygroove 166, part of oil flows into the oil storage unit 167 during theoperation of the compressor, and the oil may be maintained even when thecompressor is stopped. Then, when the compressor is restarted, oilfilled in the oil storage unit 167 is released to lubricate between thekey groove 166 and the key portion 175. Accordingly, oil shortagebetween the key groove and the key portion may be prevented in advancewhile restarting the compressor.

On the other hand, in a motor-driven compressor according to the presentinvention, still another embodiment of the oil storage unit will bedescribed as follows.

In other words, in the foregoing embodiments, a groove for storing oilis formed in the key groove of the frame and the key groove of thesecond scroll, in which an oldham ring or a key portion of the oldhamring is inserted, but in the present embodiment, an oil storage memberis inserted into a position where an oil storage unit is formed in theabove-described embodiments. FIGS. 18 and 19 are a perspective view anda cross-sectional view showing an example in which an oil storage memberaccording to the present embodiment is coupled to a key portion of theoldham ring. Hereinafter, the key portion 175 inserted into the keygroove 166 of the second scroll among the plurality of key portions willbe described, but the other key portions are the same.

As illustrated in the drawings, the oil storage unit 175 d having apredetermined width and depth is formed in the key portion 175 of theoldham ring 170, and an oil storage member 176 may inserted into andcoupled to the oil storage unit 175 d.

The oil storage unit 175 d may be formed not only in a groove shape butalso in a hole shape as described above. However, in order to form theoil storage unit 175 d in a hole, it may be applicable to a case wherethe oil storage capacity of the oil storage member 176 is remarkablyhigh. Accordingly, the oil storage unit 175 d may be formed at the sameposition as illustrated above in FIG. 13A. However, in the case of thepresent embodiment, since the oil storage member 176 is inserted intothe oil storage unit 175 d, the oil storage unit 175 d may be coupledthereto in a direction parallel to the ground, that is, a horizontaldirection of the key portion 175.

The oil storage member 176 may be formed of a material or a shapecapable of containing oil, but may be preferably formed of a materialhaving a porous shape as well as a predetermined strength as shown inthe drawing. When the oil storage member 176 has a predeterminedstrength, even if the width and depth of the oil storage portion 175 dare somewhat increased, the strength of the oil storage portion 176 canbe increased by the oil storage member 176. [In this case, an axialcross-sectional area of the oil storage unit 175 d or the low oil member176 may be formed to be larger than or equal to the that of the keyportion 175.

Even when the storage oil member is inserted into and coupled to the oilstorage groove as described above, the basic structure or theoperational effect thereof is similar to the above-described embodiment.However, in the present embodiment, oil stored in the oil storage unit175 d may be more effectively preserved as the oil storage member 176having an oil storage capacity is inserted into the oil storage unit 175d. In addition, as the storage member 176 itself has a predeterminedstrength, the strength reduction of the key portion 175, which may begenerated while the oil storage unit 175 d is formed in the key portion175, may be suppressed, thereby preventing the key portion 175 frombeing broken.

Meanwhile, another embodiment of the oldham ring according to thepresent disclosure will be described as follows.

In other words, in the above-described embodiment, the ring portion andthe key portion of the oldham ring are formed as a single body, but thepresent embodiment may be similarly applicable to a case where the ringportion and the key portion of the oldham ring are fabricated andassembled respectively. FIG. 20 is an exploded perspective views showinga state in which a key portion is separated from a ring portion toexplain another embodiment of an oldham ring in a motor-drivencompressor according to the present embodiment.

As illustrated in FIG. 20, a fixed groove 171 a and a fixed protrusion175 f may be formed on the ring portion 171 and the key portion 175,respectively, so that the ring portion 171 and the key portion 175 ofthe oldham ring can be separately fabricated and assembled, but the keyportion 175 can be fixed to the ring portion 171. Of course, the fixedgroove and the fixed protrusion may be formed on opposite sides to eachother.

Furthermore, the key portion 175 may be formed with the oil storage unit175 d described above. Of course, the oil storage member (not shown)described above may be inserted into and coupled to the oil storageunit.

Even when the ring portion 171 and the key portion 175 are assembled andformed as described above, the basic structure and effects are the sameas those of the above-described embodiments. However, when the ringportion 171 and the key portion 175 are assembled and formed as in thepresent embodiment, the materials of the ring portion 171 and the keyportion 175 may be formed differently if necessary.

For example, the ring portion 171 of the oldham ring is formed of alightweight material such as aluminum because the ring portion 171generates less friction than the key portion 175, whereas the keyportion 175 may be formed of a steel or iron material having wearresistance. Thus, it may be possible to suppress the key portion frombeing damaged due to wear-out while reducing the overall weight of theoldham ring.

On the other hand, in the above case, the key portion itself of theoldham ring may be formed in a form capable of storing oil. FIG. 21 isan exploded perspective views showing a state in which a key portion isseparated from a ring portion to explain still another embodiment of anoldham ring in a motor-driven compressor according to the presentembodiment.

As shown in FIG. 21, the ring portion 171 is formed of a lightweightmaterial such as aluminum as described above, whereas the key portion175 may be formed of a material having wear resistance as compared toaluminum. In this case, the key portion 175 may be formed of a porousshape or material so as to have an oil storage effect.

Accordingly, even when the compressor is stopped, oil flowing betweenthe key portion 175 and the key groove (not shown) remains in fine holesor fine grooves provided in the key portion 175 to lubricate between thekey portion 175 and the key groove when the compressor is restarted.

On the other hand, even when the foregoing reinforcement member isinserted into the key portion according to the present embodiment, theoil storage unit may be formed in the key portion. However, when the oilstorage unit may be formed in the key portion, a communication hole maybe formed on a surface of the reinforcing member facing the oil storageunit to efficiently supply oil to the oil storage unit.

FIG. 22 is an exploded perspective view showing a reinforcing member ina key portion of an oldham ring according to the present embodiment, andFIG. 23 is a fractured perspective view showing the key portion and thereinforcing member in a state in which the reinforcing member isassembled to the key portion of the oldham ring in FIG. 22.

For example, as shown in FIGS. 22 and 23, some of the key portions 175may be arranged in a horizontal or substantially horizontal direction.Of the key portions, for the key portion 175 arranged in a horizontal orsubstantially horizontal direction, the foregoing oil storage unit 175 dmay be formed on a circumferential one side surface, more precisely, ona sliding side surface 175 c positioned on the upper side.

Here, the upper sliding side surface 175 c is surrounded by thereinforcing surfaces 181 a, 181 b, 181 c of the reinforcing member 180together with a lower sliding side surface 175 c and an outercircumferential side surface 175 a on an opposite side thereto. Then,the oil storage unit 175 d provided on the upper sliding side surface181 b is closed by the first reinforcing surface 181 a. Then, oilflowing into the key grooves 146, 166 is guided to the oil storage unit175 d by the reinforcing member 180 and discharged as it is withoutbeing stored.

However, when the communication hole 186 is formed in the firstreinforcing surface 181 a of the reinforcing member 180 facing the oilstorage unit 175 d, as illustrated in the present embodiment, oilflowing into the key groove is efficiently moved to the oil storage unit175 d through the communication hole 186 to store oil in the oil storageunit 175 d. The resultant operational effect are the same as those ofthe above-described embodiments, and the description thereof will beomitted. Of course, although not shown in the drawing, a clearance maybe generated between the reinforcing member and the key portion due to amachining error or an assembly error, and oil may flow into the oilstorage unit through the clearance. In this case, even when thecommunication hole is not formed in the reinforcing member, part of oilmay be stored in the oil storage unit.

In addition, in the foregoing embodiments, a low-pressure scrollcompressor in which an inner space of the casing constitutes a suctionspace has been described, but the present disclosure may be similarlyapplicable to a high-pressure scroll compressor in which an inner spaceof the casing constitutes a discharge space.

What is claimed is:
 1. A scroll compressor, comprising: a first scroll;a second scroll engaged with the first scroll and configured to performan orbiting movement, the second scroll forming a compression chamberbetween the first scroll and the second scroll; an oldham ring includingan annular ring portion and a key portion protruding axially from thering portion, the key portion being slidably coupled to a key grooveprovided in the second scroll to allow the second scroll to perform anorbiting movement with respect to the first scroll; and a reinforcingmember coupled to the key portion of the oldham ring, the reinforcingmember being positioned between the key groove of the second scroll andthe key portion of the oldham ring.
 2. The scroll compressor of claim 1,wherein the reinforcing member comprises: a plurality of reinforcingsurfaces facing sliding side surfaces of the key portion; a connectingsurface connecting the plurality of reinforcing surfaces, the connectingsurface facing an outer circumferential side surface of the key portion;and a plurality of fixing surfaces extending from the respectivereinforcing surfaces towards each other adjacent an innercircumferential side surface of the key portion, the fixing surfacesfacing the inner circumferential side surface of the key portion.
 3. Thescroll compressor of claim 2, further including: a release preventinggroove extending radially from the inner circumferential side surface toa predetermined depth, and release preventing portions extending fromthe fixing surfaces into the release preventing groove.
 4. The scrollcompressor of claim 2, further including: a release preventing grooveextending radially from the inner circumferential side surface to apredetermined depth, the release preventing groove including one endopen in an axial direction, and release preventing portions extendingfrom the fixing surfaces into the release preventing groove.
 5. Thescroll compressor of claim 2, further including a release preventinggroove extending radially from the inner circumferential side surface toa predetermined depth, the release preventing groove extending to boththe sliding surfaces of the key portion, wherein both the fixingsurfaces of the reinforcing member are inserted into the releasepreventing groove.
 6. The scroll compressor of claim 2, furtherincluding release preventing grooves having a predetermined depth formedon both circumferential side surfaces of the key portion, and releasepreventing portions protruding from both reinforcing surfaces of thereinforcing member into the release preventing grooves.
 7. The scrollcompressor of claim 1, wherein the reinforcing member comprises a firstreinforcing member provided to face one sliding surface of the keyportion and a second reinforcing member provided to face the othersliding surface of the key portion.
 8. The scroll compressor of claim 7,further including release preventing grooves having predetermined depthsformed respectively on an outer circumference side surface and on aninner circumferential side surface of the key portion, respectively, andthe first reinforcing member and the second reinforcing memberrespectively comprising: reinforcing surfaces facing both sliding sidesurfaces of the key portion, fixing surfaces extending from both ends ofthe reinforcing surfaces, and release preventing portions extending fromthe fixing surfaces into the release preventing grooves.
 9. The scrollcompressor of claim 1, wherein the reinforcing member comprises: aconnecting surface facing one axial side surface of the key portion; anda plurality of fixing surfaces respectively bent at both ends of theconnecting surface to face both circumferential side surfaces of the keyportion.
 10. The scroll compressor of claim 1, wherein an oil storageunit is provided at one of the oldham ring or a member to which theoldham ring is coupled.
 11. The scroll compressor of claim 10, whereinthe key portion is one of a plurality of key portions formed atintervals along a circumferential direction on the ring portion to beslidably inserted into key grooves provided in the frame or in thesecond scroll, and wherein the oil storage unit comprises a recess inthe key portion.
 12. The scroll compressor of claim 11, wherein the keyportion includes a key root portion and a protrusion extending axiallyfrom the key root portion and the oil storage unit is formed in theprotrusion.
 13. The scroll compressor of claim 10, wherein the oilstorage unit comprises an oil storage member capable of containing oil.14. The scroll compressor of claim 10, wherein the reinforcing memberincludes a communication hole facing the oil storage unit.
 15. Amotor-driven compressor, comprising: a first scroll; a second scrollthat forms a compression chamber between the first scroll and the secondscroll while being engaged with the first scroll to perform an orbitingmovement; a frame fixed in a radial direction on an opposite side of thefirst scroll with the second scroll interposed therebetween to supportthe second scroll in an axial direction; and an oldham ring coupledbetween the second scroll and the frame or between the second scroll andthe first scroll to suppress the rotation of the second scroll, whereinan oil storage unit is provided at one of the oldham ring or a member towhich the oldham ring is coupled.
 16. The motor-driven compressor ofclaim 15, wherein the oldham ring comprises: an annular ring portion;and key portions formed at intervals along a circumferential directionon the ring portion to be slidably inserted into key grooves provided inthe frame or in the second scroll, at least one key portion of the keyportions including the oil storage unit, wherein the key portionincludes a key root portion and a protrusion extending axially from thekey root portion and the oil storage unit comprises a recess formed inthe protrusion.
 17. An oldham ring, comprising: an annular ring portion;at least one key portion protruding axially from the ring portion, thekey portion being configured to be slidably coupled to a key grooveprovided in one of a scroll or a frame coupled to the oldham ring; and areinforcing member coupled to the key portion of the oldham ring, thereinforcing member comprising: a plurality of reinforcing surfacesfacing sliding side surfaces of the key portion; and a connectingsurface connecting the plurality of reinforcing surfaces and facing anouter circumferential side surface of the key portion.
 18. The oldhamring of claim 17, wherein the key portion is a first key portionprotruding axially from the ring portion in a first direction, and theoldham ring further includes a second key portion protruding axiallyfrom the ring porition in a second direction opposite the firstdirection.
 19. The oldham ring of claim 18, wherein the ring portionincludes a groove and the key portion includes a protrusion slidinglyreceivable in the groove.
 20. The oldham ring of claim 19, wherein thekey portion comprises a porous material configured to store oil.